The present invention relates to a digital type of composite image processing apparatus into which a plurality of image processing devices, such as an image communications device which sends or receives image information or other data over a network, an image input device such as a scanner, a printing device, an image storage device, an image editing device, etc., are integrally incorporated, and more specifically to an image processing apparatus which has at least a facsimile function built in.
In recent years, digital complex image processing apparatuses--the so-called multifunction copying machines--have been developed actively, which integrally incorporate various image processing devices, such as an image input device such as a scanner, an image storage device such as a hard disk or optical disk, an image communications device using a facsimile or network, a printer, an image editing device, etc. Conventionally, these apparatuses use an image memory dedicated to fax data storage.
Normally, a received image is stored in an image memory and then read immediately for printing. The image in the memory is subsequently erased. Accordingly, all the free space of the image memory will not be occupied by received data and failure to receive due to insufficient amount of memory seldom occurs.
However, if a problem arises in security when fax data received at night is printed out as it is, it is required to preserve all fax data received at night without being printed out. In such a case, a situation may occur in which the image memory becomes full of image data received at night, resulting in failure to receive.
Such a situation does not occur so frequently even with conventional digital composite image processing apparatuses having a function of storing data received at night in an image memory.
This is mainly due to the fact that the amount of memory required to store a page of received data is not so large because the resolution of image data handled so far is not so high.
In recent years, however, the quality of faxes has been improving and the resolution has a tendency to become very high. With improving image quality, photo images may be transmitted with quasi-halftones added. And transmission in color has also been progressing. For this reason, fax image data has a tendency to increase in size and hence it is becoming difficult to store all data received at night in a memory dedicated to fax reception.
Means for solving these problems include increasing the size of memory for fax reception and preparing a large-capacity external storage.
However, for example, providing a large-capacity memory which is not much needed usually for the purpose of adapting to a special situation such as night will reduce the efficiency of the resource utilization in the apparatus and increase the cost of the apparatus.
Thus, even if fax quality, such as resolution, improves and fax image data increases in size, it is required to store all data received at night from the standpoint of security. However, the conventional memory dedicated to fax reception has limited storage capacity. An insufficient amount of memory may result in failure to receive, causing line disconnection. The provision of a large-capacity dedicated memory results in an increase in cost and decreased efficiency of memory utilization in the whole apparatus.